1. Field of the Invention
The present invention relates to a chain and flight conveyor for use in conveying materials in the mining industry, and, in particular, to an improved design for the attachment of flights to conveyor chains.
2. Description of the Prior Art
In the process of underground mining, material is removed from a seam and transferred between machines which employ conveyors. Mined material is often transported and conveyed in shuttle cars or rock crushers that have a flat deck and conveyor chains which are designed specifically to load and unload the material there from. In most applications, the conveyor chains in the shuttle cars consist of two drive chains which are positioned on the extreme outer borders of the conveying decks of the cars. The drive chains consist of roller links, which contact the drive sprockets of the machine, and connecting links which are positioned between the roller links. In addition, the conveyor chains have flights which are fixed to the two drive chains and are positioned between the two chains. These flights are usually made of steel and can be a welded, tubular design or a solid, one piece design. The conveyor chain flights are positioned along the drive chains in a spacing designed to efficiently move material in the shuttle car. The flights are usually connected to the drive chains by inserting a male member on the ends of the flights through slots which are located in the roller links of the drive chains.
The prior designs have had disadvantages in several respects. In most previous designs, attachment and removal of the flights from the conveyor chains has been difficult, many times necessitating removal of the chain links to replace a flight. The drive chains in most prior designs must be moved from their normal operating position on the sprockets in order to connect the flights to the chains. In addition, forces experienced during the operation of a shuttle car which destroy the flights are transferred to the drive chains and often cause failures of those chains.
One prior art conveyor chain design appears in French Patent No. 665,420 issued to Naranovitch. That patent teaches of a conveyor chain in which the links include individual wheels. Certain links are designed differently and have a male extension fitting into a vertical U-shaped hinge element on the end of the flight. The attachment is secured by a pin. This patent, however, does not relate to a roller link arrangement which is driven by a drive gear. Also, the pins interconnecting the flights and the modified links are subjected to pure shear forces. Another design for a conveyor chain appears in U.S. Pat. No. 2,575,610 issued to Ball. That patent discloses parallel chains having flights with a male projection member thereof fitting into openings in predetermined chain links. This projection is slightly smaller than the opening thereby allowing for a small degree of tilt. Thus, the flight is pivotally connected to the side chains and replacement of flights requires that the chain be removed from the drive sprockets to remove a flight. Yet another design appears in U.S. Pat. No. 3,089,579 issued to Beck. The Beck patent teaches a conveyor flight with a removable, outwardly projecting male extension member which fits into openings in certain links on the chain. This extension is fastened to the flight by means of an interlocking tongue and groove mechanism fastened by bolts. As such, the flight may be removed from or attached to the conveyor chain without disturbing the chain tension or removing the entire load. However, in this apparatus the male extension member enters the conveyor chain and prohibits engagement of the conveyor drive sprocket with predetermined links along the chain. In yet another design, the ends of each flight include longitudinally extending bores, and journal pins that connect connecting links to roller links extend into the bores. As in the other earlier designs, the chain must be disassembled in order to replace the flight.
Edmondson U.S. Pat. No. 5,000,310 addresses many of the short comings of the above designs by providing a special link that replaces some of the roller links, the special link including a male member that extends inwardly toward the other chain, with specially designed flights having female ends that are positioned around the male extensions of the special links. In addition to the requirement of having a special link, this design further has the disadvantages of having the joint between the male member and the female ends exposed to the material in the flight conveyor, as well as having the principal piece, a bolt and nut that holds the female end on the male member, exposed to the materials.
The subject invention is directed toward an improved design for attachment of flights to a chain and flight conveyor which overcomes, among others, the above discussed problems and which provides for a more useful means of flight attachment which does not require a disruption of the conveyor chain for flight replacement and which allows all roller links to be engaged by the conveyor chain drive gears of the shuttle car. This new design enables attachment of the flights to the drive chains without repositioning the drive chains from their normal operating position.
In accordance with the present invention, there is provided an improved design for a chain and flight conveyor. Two drive chains are positioned on the perimeter of a flat horizontal deck of a shuttle car used in mining operations. Flights run between the chains and sweep material along the deck. The flights are usually made of steel and can be a welded, tubular design or a solid, one piece design.
More particularly, the invention provides a chain and flight conveyor adapted to be driven by a toothed sprocket comprising a pair of spaced apart, parallel driving chains, each of the driving chains comprising roller links having at least one end surface which may be drivingly engaged by the teeth of the sprocket. The roller links also have internal apertures defining drive surfaces which may be drivingly engaged by the teeth of the sprocket. The driving chains further include connecting links coupled to and interconnecting the roller links, and pins pivotally connecting the connecting links to the roller links.
A predetermined corresponding number of the pins on each of the chains comprises extended flight attachment pins having pin extensions facing the opposite chain. A plurality of conveying flights are connected between the corresponding number of the pin extensions, the flights comprising a bar member having two opposite ends, four sides and a bottom surface. The bar member bottom surface has at least one indentation provided on the bar member ends, each of the indentations being adapted to receive its respective pin extensions. The flight further includes a bolt extending through the flight sides forming the indentation, the bolt being secured to the flight so that the pin extensions are held in the indentations.
Accordingly, the present invention provides solutions to the aforementioned problems encountered in the utilization of chain and flight conveyors in shuttle cars. As this invention provides flight attachment links with extended pins to which the flights are attached, the problems caused by the necessity to remove or disrupt the conveyor chains to replace or repair flights are alleviated.
These and other details, objects, and advantages of the invention will become apparent as the following description of the preferred embodiment thereof proceeds.